Research

Research summary

C4 photosynthesis and gene discovery in model plants for second generation lignocellulosic feedstocks

Research description

The Brutnell lab is located at the Donald Danforth Plant Science Center in St. Louis, Missouri.

A major thrust of the research in the Brutnell lab focuses on the use of new model grasses as drivers for lignocellulosic feedstock development and to improve productivity of major cereal crops. This includes developing genetic resources for Setaria viridis and Brachypodium distachyon. S. viridis is a small, self-pollinating diploid and is a member of the panicoid clade of grasses that includes maize, sugarcane, sorghum, Miscanthus and switchgrass. B. distachyon is also a small, self-pollinating diploid grass and is a member of the Pooideae clade that includes wheat, barley, rye and several turf grass and forage species. The genomes of both species have recently been sequenced and transformation technologies have been developed for each. Members of my group have contributed to the development of transformation technologies for S. viridis and we have helped annotate the S. viridis and B. distachyon genomes. We are currently developing genetic resources for both systems that include chemically- and radiation- mutagenized populations. We are also tapping high-throughput sequencing techniques to accelerate reverse and forward genetic screens and to develop a gene atlas for S. viridis using RNAseq technology.

Another important component to his research program is the development of reverse genetics tools for gene discovery in maize. Over the past ten years, members of the Brutnell lab have been mobilizing and mapping the maize transposable elements Ac and Ds insertions throughout the maize genome. They have also been developing genetic and molecular protocols for using Ac and Ds as insertional mutagens. These elements tend to insert at closely linked sites in the genome to create unstable genetic variation. They have shown how these transposons can be used to fine map gene structure and have several targeted mutagenesis programs underway.

Finally, a fundamental biological challenge that Brutnell is trying to address in the lab is to understand the mechanisms that drive C4 photosynthetic differentiation. Using the forward and reverse genetics resources we have developed for S. viridis and Z. mays, we are now generating mutants in the genes necessary for the C4 carbon shuttle and using a combination of informatics and molecular approaches to define the regulatory networks driving their expression. These studies are targeted at understanding the function of genes involved in C4 photosynthesis and have applications in breeding/engineering improved photosynthetic traits in C4 grasses and in introducing novel C4 traits into C3 grasses.